The present disclosure relates to a printing and imaging apparatus, particularly to a method, a system and a memory chip for generating a verification value.
With respect to a printing and imaging apparatus, such as an inkjet printer, an electrophotographic printer (including laser printer and LED printer), and a photocopier, etc., printing supplies thereof are usually mounted in a removable manner, so that the user can replace the printing supplies and maintain the apparatus after the supplies run out. The printing supplies comprise an ink cartridge, a toner cartridge, and a drum cartridge, which are collectively called as imaging cartridge.
In order to record the states of the imaging cartridges, so that they can be managed centrally by the printing and imaging apparatus, a memory chip is mounted thereon. The memory chip stores information about the imaging cartridge, such as the product model, colors and types of the recording materials (such as ink and toner), and the production date, etc.
In this case, the printing and imaging apparatus can acquire the situation of the imaging cartridge by reading the information in the memory chip. Since the imaging cartridge works under hostile environment, such as vibration and humid powder, data in the memory chip on the imaging cartridge will fluctuate. Obviously, if the printing and imaging apparatus needs to read all the information in the memory chip before executing each printing operation, the ready time of the printing operation will be too long, rendering low operation efficiency.
In order to avoid the above problems, current printing and imaging apparatuses in the industry only read a part of the data and verification value from the memory chip before executing the printing operation. The memory chip obtains the verification value by calculating all the data stored therein through universal MD5 algorithm. The printing and imaging apparatus can determine whether the data stored in the memory chip is normal through reading the verification value.
When the printing and imaging apparatus requests to read the verification value, the memory chip should calculate all the data stored therein before obtaining the verification value. Such a calculation without taking the characteristics of the data into consideration is time consuming, and thus fails to follow the trend of quick response of electronic apparatus. In addition, the calculation of the verification value also wastes electricity power. In this case, with respect to a memory chip powered by a battery, its service life will be shortened.